British youngsters are becoming increasingly unhappy - and their lower well-being should not be dismissed as "teen grumpiness", The Children's Society has warned.
Younger teens are the worst affected, according to the charity's Good Childhood Report 2013, and are less likely to be happy about school, their appearance and the amount of choice and freedom they are given.
The Children's Society said for children of all ages, there had been a period of rising well-being from 1994 to 2008 but that this had started to stall and could be declining in more recent years.
Matthew Reed, chief executive of The Children's Society, said: "The well-being of our future generation in the UK is critical. So it is incredibly worrying that any improvements this country has seen in children's well-being over the last two decades appear to have stalled.
"These startling findings show that we should be paying particular attention to improving the happiness of this country's teenagers. These findings clearly show that we can't simply dismiss their low well-being as inevitable 'teen grumpiness'. They are facing very real problems we can all work to solve, such as not feeling safe at home, being exposed to family conflict or being bullied.
"It is so important that we all, from governments to professionals to parents, talk, listen and take seriously what children and teenagers are telling us."
The charity, who spoke to 42,000 children between the ages of eight and 17 for the report, said those aged 14 and 15 have the lowest life satisfaction of all children.
Psychologist Dr Linda Papadopoulos said of the report: "Interestingly, this report suggests that, when it comes to well-being, 14 and 15 year olds fare worse. It is so important that we don't simply dismiss this dip as an inevitable part of growing up, that it is just teenagers being teenagers. We really must talk to this generation and listen to what they have to say."
Emma-Jane Cross, founder and chief executive of MindFull, the mental health charity for children and young people, said: "Far too often, people overlook teenage wellbeing and mental health issues because they put the symptoms down to angst or moodiness. This damaging attitude can no longer continue when so many are desperately unhappy and struggling with serious issues including self-harm and suicidal thoughts."
Lucie Russell, director of campaigns and policy at well-being and mental health charity YoungMinds, said: "These findings must not be dismissed as simply an inevitable part of growing up. Last year our parents' helpline received a record number of calls from parents concerned about the mental health or well-being of their child. We must take notice of these warning signs and act if we are not to see children increasingly struggling to cope."